The takeaway: Auroras, or northern lights, produce captivating night skies. Humans love it–birds, not so much.

A spate of solar storms have led to a startling number of auroras in the past few years, coloring the night skies red, green, blue, purple, and even pink–and done so far south of the polar regions where these phenomena are most common.

While breathtaking to experience in person, these storms and the resulting auroras can have a negative impact on migrating birds. This blog looks at how birds are impacted–but first let’s understand what these events are.

What Is the Aurora Borealis?

The aurora borealis, or northern lights, is a natural light display in the sky that usually occurs near the polar regions. A borealis forms when charged solar wind particles from the sun collide with gas in the Earth’s atmosphere. These collisions release photons, which are seen as shimmering lights in the sky. They can appear as a curtain, arc, or spiral, and ripple or flow due to changing solar wind conditions.

What Is the Difference Between a Solar Storm and an Aurora?

A solar storm is a disturbance from the sun that shoots high-energy particles and magnetic fields toward Earth, usually from solar flares and coronal mass ejections. These storms, which are not visible to the naked eye, can wreak havoc on everything from radio communications to power grids when the energy interacts with the Earth’s magnetic field.

An aurora–in the northern hemisphere (the term is “aurora borealis” while in the southern hemisphere the term is “aurora australis”) happens when a solar storm or solar wind energizes particles in the Earth’s magnetosphere, which causes shimmering pastel-colored lights. 

Are Solar Storms Becoming More Common Or More Intense?

Yes–sort of. After a long lull, the Sun’s activity is ramping up, and key solar metrics like sunspots, solar winds, and magnetic activity have increased since 2008. We are experiencing the effects of a solar cycle, and over the next few years this cycle will reach its maximum. These cycles follow an 11-year cycle, so you should expect a higher likelihood of solar storms over the next few years–then things should taper off. And while these extreme storms are more common recently, they remain quite rare. Along with the increase in storms, the lights will continue to be seen further south than usual–meaning that people (and birds) in mid-latitude areas of North America, Europe, and Asia will have a better chance of seeing the northern lights (and those in South America, Africa, and Australia may see the southern lights).

Do Solar Storms Impact Bird Migrations?

Yes–solar storms do impact bird migrations, although the effect is usually indirect and often subtle.

Migratory birds rely on the Earth’s magnetic field as a kind of compass to find their way, and some birds also use the sun, stars, and other landmarks to get around. Magnetic sensing is key, particularly during long nighttime migrations, when visual cues are limited.

Solar storms mess up the Earth’s magnetosphere and create geomagnetic storms. The resultant “magnetic noise” can confuse birds’ navigations, causing them to become disoriented or even veer off course. During strong geomagnetic storms, some birds even delay migration or show unusual flight patterns.

Recent scientific studies show these storms mess with all sorts of animals, including whales and salmon. One study in particular used data from weather surveillance radars over a 23-year span to show how a bird migration in the central flyway of the Great Plains was impacted by a solar storm. One result was that the birds let the wind guide them, not their magnetic compass, while another was that the effects were even more pronounced when conditions were overcast. In all, there was a 9-17 percent drop in the number of birds migrating at night in both the spring and fall migrations during strong geomagnetic disturbances.

Yet another study found that during strong solar storms, migrating birds flew at a lower altitude than normal–likely to be closer to landmarks.

If Solar Storms Increase, What Will Happen to Migrating Birds?

Impacts to migrating birds from increased solar storms will be minimal, but not zero. With reduced migration activity, navigational problems, and increased energy expenditures, birds already stressed by habitat loss and climate change could be put even more at risk. Interrupted migrations could slow the breeding and nesting process, and delay childbirth and rearing.

However, keep this in mind: Bird migrations have likely been going on for tens of millions of years, and solar storms have probably happened for as long as the sun has existed–billions of years. So none of this is new. On top of that, birds are incredibly flexible and adaptable, which is why they’ve been around so long.

Which Birds Are Most Impacted By Northern Lights?

Some birds are impacted more by auroras than others. Here are some species that research suggests are particularly sensitive to geomagnetic storms.

  • Songbirds, many of which are nocturnal migrants, including Eurasian Blackcap, European Robin, Garden Warbler, and other North American warblers.
  • Waterfowl, such as mallards, geese, and swans, which migrate using magnetic cues, winds, and landmarks.
  • Raptors like hawks, falcons, and eagles, that rely on thermal soaring during the day but use magnetic cues as a secondary navigation system.

In all, nocturnal migrants are the most strongly affected, as are those who fly long distances over open water. Daytime migrants are less affected. All impacts are usually temporary, with birds changing course, if needed, once magnetic conditions normalize.

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